17cf2cb1d2
Most C standard library functions are undefined if passed NULL, even when the corresponding length is zero. This gives them (and, in turn, all functions which call them) surprising behavior on empty arrays. Some compilers will miscompile code due to this rule. See also https://www.imperialviolet.org/2016/06/26/nonnull.html Add OPENSSL_memcpy, etc., wrappers which avoid this problem. BUG=23 Change-Id: I95f42b23e92945af0e681264fffaf578e7f8465e Reviewed-on: https://boringssl-review.googlesource.com/12928 Commit-Queue: David Benjamin <davidben@google.com> Reviewed-by: Adam Langley <agl@google.com>
48 lines
1.6 KiB
C
48 lines
1.6 KiB
C
/* Copyright (c) 2016, Google Inc.
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
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* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
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* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
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#include <openssl/rand.h>
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#if defined(BORINGSSL_UNSAFE_DETERMINISTIC_MODE)
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#include <string.h>
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#include <openssl/chacha.h>
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#include "internal.h"
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/* g_num_calls is the number of calls to |CRYPTO_sysrand| that have occured.
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*
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* TODO(davidben): This is intentionally not thread-safe. If the fuzzer mode is
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* ever used in a multi-threaded program, replace this with a thread-local. (A
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* mutex would not be deterministic.) */
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static uint64_t g_num_calls = 0;
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void RAND_reset_for_fuzzing(void) { g_num_calls = 0; }
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void CRYPTO_sysrand(uint8_t *out, size_t requested) {
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static const uint8_t kZeroKey[32];
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uint8_t nonce[12];
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OPENSSL_memset(nonce, 0, sizeof(nonce));
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OPENSSL_memcpy(nonce, &g_num_calls, sizeof(g_num_calls));
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OPENSSL_memset(out, 0, requested);
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CRYPTO_chacha_20(out, out, requested, kZeroKey, nonce, 0);
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g_num_calls++;
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}
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#endif /* BORINGSSL_UNSAFE_DETERMINISTIC_MODE */
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